two children jumping into a river, in sunlight

Jumping, Diving and other River Risks

Play it safe: never jump into the unknown

Kate Rew

There are inherent and serious risks in river swimming, some of which come up if you want to throw yourself in from a height.

Every hot summer there are horrific accidents where people are killed or seriously injured jumping, diving or tomb-stoning. Nothing is without risk, and it’s impossible to have adventures without them – but to protect yourself, and to take educated risks, you need to know what dangers you face.  Here are some river hazards so you are better able to assess and moderate your risk and take a safe and enjoyable swim.

Jumping, Diving, Back Flips & Tombstoning

Jumping and diving into a deep river pool are great fun if done with some knowledge and with care, but can be dangerous.

Don’t jump into the unknown. If you can see the bottom, don’t jump, it’s too shallow. If you can’t see the bottom, don’t jump – there could be anything underneath. Submerged objects might not be visible. If you do want to jump or dive in, get in and test the depth of the area and ensure it’s clear of objects first. The shock of cold water can make it difficult to swim: getting in first also means that you will get the initial gasping response to cold water out of the way with your head above water. Parents of young children who like using rope swings often make sure their children have swum first, before they start jumping for this reason.

Be aware that river levels rise and fall: a place that has enough depth to jump one day may not the next. Also, obstructions (tree trunks, rocks) may move into what was a safe area after heavy rainfall.

Dominick Tyler

Be aware that river levels rise and fall: a place that has enough depth to jump one day may not the next. Also, obstructions (tree trunks, rocks) may move into what was a safe area after heavy rainfall.

Many experienced swimmers have warmed others off bridges or away from popular jumping spots, at times of low flow where people could be about to seriously injure themselves – pass your knowledge on wherever possible. The assumption of many summer swimmers and jumpers is that if they’ve seen people jumping from a spot before then it will be okay for them to do so.

The greater the height that a person jumps from, the greater force that they will land with – from a great enough height it can be like the body hitting concrete. This can cause neck and spinal injuries, and also deep bruising of the internal organs.  (These are marine figures but illustrative: between 2005-2021 the UK Coastguard reported dealing with over 200 incidents, with 70 injuries and 20 deaths, with around 20% of injuries spinal with people left paralysed).

Backflips bring further risks, for example from hitting heads on the way down against objects, or not coming out of the spin and entering the water in a neat pencil position (again, with the force of collision carrying the risk of spinal injury, limb injury, head injury and bruising and damage to the internal organs).

On a river, be aware that if there is a strong current it may rapidly sweep you away.  Jumping into white water carries even greater risks: your buoyancy is less in white water, and there will be currents underneath a waterfall.  Beware of undercuts where a swimmer might become trapped beneath a ledge under the water.


Weirs are generally to be avoided – some types in particular (box weirs) are fatal to trapped swimmers and kayakers. In some places you will see people swimming happily upstream in the pools formed by weirs (their purpose is to deepen the water), but where there are places that might be safe in low flows (where I live in Somerset virtually all the popular local swim spots are above weirs) the risk changes in high flow, where dangers include being swept over the weir into stopper waves below.

Don’t be tempted to slide down the face because that’s where the biggest danger lies – in the stopper at the bottom of the falls. Here, circulating currents pull you back towards the falls and under the water. In some cases it’s impossible to escape.

Also be aware that natural stoppers can be found on many upland rivers, sometimes in relatively low flows. Learn how to spot them, and if you do get caught, know how to get out.


Rocks can be both a hazard and a useful shelter against a strong current. Obviously check for rocks before jumping in, and take care when swimming; it’s all too easy to bash your ankle or knee on a submerged rock. They also tend to be extremely slippery, so bear that in mind when clambering along or in rivers.

From Wild Swim, by Kate Rew and Dominick Tyler

Obstructions, Sieves, Syphons and Strainers

Check for obstructions before you get in. Fallen trees, for example, can act as “strainers” and in tandem with the force and weight of water can hold a swimmer against the object, under the water. Many a kayaker has died in such circumstances.

Merlin's Pool ©VivienneRickmanPoole

There are other hazards such as undercuts and tree roots that might trap you in a similar way. Banks are more likely to be undercut on the outside of bends which is where the current flows fastest, and the water runs deepest. So if you do venture to the fast and deep water, be very aware of what’s ahead and bear in mind the increased force and weight of water.


outdoor swimmers handbook front cover

ABOUT THE AUTHOR: Kate Rew is the founder of The Outdoor Swimming Society and author of The Outdoor Swimmers’ Handbook (widely available and also signed in the OSS shop) which is designed to enable swimmers to assess and take risks.

  • DISCLAIMER: The OSS believes that with the right to swim freely comes the responsibility to do it safely. Risk is inherent in most activities and all adventures. Swimmers take sole responsibility for all risks that they incur in making their own personal decisions about whether to swim. See our Swim Responsibility Statement.
  • This feature has evolved from a piece written by an early OSS team member, Lynne Roper, who worked with Kate on the creation of this ‘Survive’ section many years ago, and whose diaries Wild Woman Swimming (printed posthumously) are a brilliant wild swimming read: full of spirit and poetry.
Kate Rew  (@kate_rew)